[Getdp] sample of time steps
Christophe Geuzaine
christophe.geuzaine at case.edu
Thu Feb 23 20:25:11 CET 2006
David Felsenthal wrote:
> I am doing a non-linear simulation, and am saving a sub-set of the
> calculated solutions. I have:
>
> Function {
> .
> .
> .
> dt = 0.001;
>
> SaveFct[] = !($TimeStep % ((1/dt)/100));
>
>
> }
>
> and
> Resolution {
> { Name nonlinear;
> System {
> { Name T; NameOfFormulation The_T; }
> }
> Operation {
> InitSolution [T];
> SaveSolution [T];
> TimeLoopTheta [t0 , t1 , dt, 1.] {
> IterativeLoop[NL_NbrMaxIter, NL_Eps, NL_Relax] {
> GenerateJac [T] ; SolveJac [T] ;
> }
> Test [ SaveFct[] ] { SaveSolution [T]; }
> }
> }
> }
>
>
> When I do
>
> getdp -v 0 box.pro -solve nonlinear; getdp box.pro -pos pos
>
> from the command line all works as expected, I get a sub-set of the data
> points.
>
> If I type:
>
> getdp -v 0 box.pro -solve nonlinear -pos pos
>
> I get all the data points. I didn't expect this behavior. Is this expected?
>
It is expected (although I agree it can be a little confusing ;-).
Your test on SaveFct[] only changes the solutions that are saved in the
resolution file (.res). When you do the post-processing at the same time
as the resolution, all the solutions are available in memory and they
are all used (we don't read the .res file in that case). If you
post-process after the computation is done, only those solutions that
have been saved in the file are available, so only those solutions are used.
One "fix" for this is to actually execute the post-processing operations
inside the resolution using the "PostOperation[..., LastTimeStepOnly];"
command, that you add inside your test (then you don't need to use
"-pos" at all).
Or you could play with the TimeStep option in the PostOperation (but it
can get tricky if you want to use both combined and separate
post-processing steps).
The easiest is probably to just do the -solve and the -pos steps
separately...
>
> Thanks,
>
> David Felsenthal
>
> p.s. Sorry about sending this to the gmsh list.
>
>
>
>
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>
--
Christophe Geuzaine
Assistant Professor, Case Western Reserve University, Mathematics
http://www.case.edu/artsci/math/geuzaine